Many analytical techniques employed today in a variety of different applications involve determining the presence or absence of a substance, i.e., an analyte, in a sample. Chemiluminescent assays are among the most sensitive assays for analytes in a sample that can be achieved by optoelectronic means. In such assays, an enzyme converts a substrate to a chemiluminescent product in the presence of an analyte of interest, where light emitted by the product is then detected as an indicator of the presence of analyte in the sample being assayed. One well-known and often used chemiluminescent substrate is luminol (3-aminophthalhydrazide or 5-amino-2,3-dihydro-1,4-phthalazinedione). In the presence of a peroxidase and peroxide, luminol is converted to a product that emits light by a chemiluminescent mechanism.
As is known in the art, luminol has a peak emission of around 425 nm. This peak emission wavelength makes luminol-based signal producing systems less attractive for use in conjunction with silicon-based detectors, since silicon-based detectors are not very sensitive in this emission region.